But the BBC’s expert analyst rated Andy Murray’s chances of a first title this year at no better than fourth best.

McEnroe tipped Murray to triumph at the Australian Open earlier this year, when Murray was dismantled by Roger Federer, and asked about his chances of breaking his Grand Slam duck at Wimbledon next week he said: “Andy Murray’s chances? Pretty good, although I’m not as confident as last year.

“He did get to the final in Australia and I’m not exactly sure what’s happened since then.

“He doesn’t seem the same and I’ve looked at it from a lot of different ways wondering what’s going on and I haven’t come up with a good answer.

“Whether it’s something off the court, whether something’s bothering him physically, whether he’s just lost his confidence, I don’t know. Maybe he’s over trained or over-tennised a little, it’s really hard to say.

“Having said that I’d still put him as the guy with the fourth best chance of winning it.

“He got to the semis last year and I could easily see him doing it, but Roger played amazingly in Australia to beat him.

“The pressure’s not the same for Roger because he’s broken every record and that makes it a little dicier and tricker for guys who haven’t won.”

Before McEnroe entertained the crowds on centre court, Frenchman Paul-Henri Mathieu and Norway’s Frederik Sletting-Johnsen kept the early spectators warm in a topsy turvy encounter.

Mathieu edged a tight opening set on a tiebreak before Freddie turned the tie on its head with a 6-1 second set success.

With the winner set to contest this afternoon’s men’s final, a Championship Tiebreak to decide the match was fiercely fought.

Mathieu eventually prevailed 10-7, but Sletting-Johnsen won plenty of friends with his sparkling shots and never say die spirit.

Ormskirk’s Barry Cowan – the man who gave Pete Sampras the biggest fright of his Wimbledon reign – and youngster Luke Bambridge were the day’s first winners. They beat Paul McNamee and Neal Skupski in a men’s doubles clash on Centre Court.

McEnroe will be back at Calderstones Park this afternoon and again tomorrow, before joining the BBC commentary team at Wimbledon.

There are a handful of tickets still left for both days at the Box Office at Calderstones Park or by visiting www.liverpooltennis.co.uk